package com.DateTest;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        String[] s1 = s.split(" ");
        int len = s1.length;
        if (len == 0 || s1[0].equals(""))
        {
            System.out.print(-1);
            return;
        }
        List<Integer> list = new ArrayList<>();
        int max = Integer.parseInt(s1[0]);
        int min = Integer.MAX_VALUE;
        int count = 0;
        for (int i = 1; i < len; i++)
        {
            if (Integer.parseInt(s1[i]) == Integer.parseInt(s1[i - 1]))
            {
                continue;
            }
            if (Integer.parseInt(s1[i]) >= max)
            {
                if (Integer.parseInt(s1[i]) - max <= min)
                {
                    min = Integer.parseInt(s1[i]) - max;
                }
                max = Integer.parseInt(s1[i]);
            }
            else
            {
                if (max - Integer.parseInt(s1[i]) <= min)
                {
                    count++;
                    System.out.print(i + " ");
                }
            }
        }
        if (count == 0)
        {
            System.out.print(-1);
        }

    }
}
